When I start the car on cold days, I hear a grinding noise that is not constant, but almost more like a grinding rattle. I need some help here. Thats about all the info I know, only happends on really cold days, and only on the first start after the car has sat overnight.

 

Doesnt anyone have any ideas?

 

if it is only when you crank it it would most likely be the starter gear meshing with the ring gear incorrectly.. this would need to be re-shimmed...if it continues after it is started it sounds like you have an accessery bearing problem

 

Maybe a starter drive on the verge of going south? A cold piece of steel could have slop that goes away when it warms up. A grinding starter usually needs a shim to align it, but with the temp. equation, I dunno. Maybe the starter is just loose, and the case clearance decreases when it warms up?

 

shim, or bendix gear